1. Field of the Invention
The present invention relates to the manufacture of semiconductor devices, more particularly, to a method for removing the circumferential edge of a dielectric layer to prevent the formation of dielectric particles, which result in contamination of the semiconductor wafer.
2. Description of the Related Art
One of the fabrication steps in the manufacture of integrated circuit devices is to apply a dielectric layer over a semiconductor wafer as an inter-metal-layer or passivation layer. The dielectric layer is in general a silicon-containing glass, such as silicon oxide, borosilicate glass (BSG) phosphosilicate glass (PSG), or borophossilicate glass (BPSG) The dielectric layer located at the circumference of the semiconductor wafer is easily peeled off during subsequent steps such as metal deposition, chemical-mechanical polishing (CMP), or thermal annealing. These peeling dielectric particles can cause contamination of the semiconductor wafer.
FIGS. 1A and 1B are cross-sections respectively showing the semiconductor with a coated dielectric layer and a peeled dielectric layer in accordance with the prior art.
Referring to FIG. 1A, a semiconductor wafer 10 having a dielectric layer 12 on its upper surface is provided.
Next, as shown in FIG. 1B, after a series of subsequent steps, such as thermal process, the dielectric layer 12 located at the edge of the semiconductor wafer 10 is peeled, generating dielectric particles 15. These peeling dielectric particles 15 can cause contamination of the semiconductor wafer. Accordingly, the performance of the semiconductor devices built on the semiconductor wafer will suffer.
In view of the above disadvantages, an object of the invention is to provide a method for removing the circumferential edge of a dielectric layer on a semiconductor wafer. According to the method, the dielectric particle problem can be eliminated so as to improve the performance of semiconductor devices.
Accordingly, the above objects are attained by providing a method for removing the circumferential edge of a dielectric layer on a semiconductor wafer, comprising the steps of: (a) providing a semiconductor wafer having a dielectric layer on its upper surface; (b) securing the semiconductor wafer on a susceptor; (c) removing the circumferential edge of the dielectric layer by a ring cutter; and (d) cleaning the semiconductor wafer from the central portion to the edge portion of the semiconductor wafer by water jets. The ring cutter preferably has sawteeth. Moreover, a wafer plate or the like can be used to replace the susceptor.
In an embodiment of the invention, the dielectric layer is silicon-containing glass such as silicon oxide, borosilicate glass (BSG), phosphosilicate glass (PSG), borophossilicate glass (BPSG), low dielectric constant material and the like.
Also, to enhance the adhesion between the susceptor and the semiconductor wafer, the susceptor can have sawteeth attaching the lower surface of the semiconductor wafer. It can also be pumped to create a vacuum to fix the position of the wafer.
In another embodiment of the invention, in the method for removing the circumferential edge of a dielectric layer, the circumferential edge of the dielectric layer is preferably removed until the upper surface of the semiconductor wafer is exposed.
In another embodiment of the invention, in the method for removing the circumferential edge of a dielectric layer, the susceptor can be rotatable susceptor.
Furthermore, the above objects are also attained by providing a method for removing the circumferential edge of a dielectric layer on a semiconductor wafer, comprising providing a semiconductor wafer having a dielectric layer on its upper surface, and then removing the circumferential edge of the dielectric layer with a cutter.